Abstract: An ultrasonic transducer system comprising a transducer array, control circuit and display system wherein the control system is able to actuate the transducer elements in groups of N and N+1 elements, actuate the groups in non-sequential order, actuate groups of selectively different sizes, subject the actuation signals to and the echo signals from the transducers to pre-programmable delay periods, compress the echo signals into a logarithmic representation, transform the echo signals into plural simultaneous visual displays on a standard TV monitor in split screen format, and transform the display of discrete points in the visual display into continuous lines. Further, each transducer element in the array may consist of a split or paired set of transducers.

Abstract: An ultrasonic transducer assembly and system including a disc-shaped transducer element surrounded by ring-shaped transducer elements of different width to permit dynamic focusing and minimum phase cancellation. The elements are switched so that the output signals for various depths have a small dynamic range whereby the dynamic range of associated amplifiers is significantly reduced.

Abstract: In an illustrated embodiment an array of ultrasonic transducer elements is combined into a first transmitting surface to emit a first transmit signal, and then in alternation with blanking intervals is combined into receiving surfaces of progressively increased size for the reception of echo signals and for constructing a first image line of a first partial image. A second transmitting surface of lesser size then emits a transmit signal and further combinations of transducer elements are activated during time intervals thereafter which correspond to the blanking intervals of the first image line. Such sequential lines may form a composite line on a visual display. A planar array of transducer elements may have its successive receiving surfaces of varying size electronically focused either in the scan direction or in the layer thickness direction, or the array can have mechanical curvature to provide a desired focus in the layer direction.

Abstract: In an ultrasound transmitting or receiving apparatus, a plurality of ultrasound transducer elements comprising an ultrasound probe are arranged along a line to transmit and receive ultrasonic waves. For the purpose of sequentially transmitting and receiving an ultrasound beam through the transducer elements, variable-delay circuits are provided for applying delay times to the transmitting signals and/or the received signals. The variable-delay circuits include memory control devices, the addresses of which correspond to the respective azimuthal directions of transmitting and receiving the ultrasound beam. The outputs of the memory devices are connected to control terminals of transfer switches, which in turn are connected to tapped delay lines. The memory devices produce control codes such that the tapped delay lines produce predetermined delay times which control the azimuthal directions of transmitting or receiving the ultrasound beam.

Abstract: In an ultrasonic transducer probe having multiple rotating transducer elements the transducer outputs are switched in response to sine and cosine signals from a resolver. The same signals are used to switch and time the display scan. If the transducers are misaligned a multiple blurred image may result. It is proposed to modify the resolver signals changing the phase of the signals for at least one transducer to bring the display signals into registration. In one example it is achieved by, for at least one transducer element output, mixing a proportion of at least one of the sine and cosine signals with the other.

Abstract: A system for selectably electrically pulsing each of a plurality of ultrasonic transducers in a testing apparatus in rapid sequence to produce a pattern of ultrasonic energy transmitted into and subsequently received from a test piece comprises a plurality of transducer pulsing circuits, each connected to a different associated one of the transducers. Each pulsing circuit includes a silicon control rectifier connected to ground and a capacitor, connected between the rectifier and the associated transducer, that is dischargeable to pulse the associated tranducer. The rectifier is switchable to an "on" condition to rapidly discharge the capacitor to ground. The rectifier maintains the "on" condition until current conducted through it drops below a characteristic holding current and thereafter switches to an "off" condition.

Abstract: An imaging system, particularly useful for acoustic medical diagnosis of a human subject, utilizes an array of radiating elements or sonic transducers located side-by-side and positioned along the subject. Signals received by the transducer are applied to a pair of pattern generation circuits which weight the individual signals by factors of +1, -1 or 0. Graphs of the weighting factors as a function of transducer location have the likeness of cosinusoidal and sinusoidal Fresnel patterns, these patterns being produced by the two circuits. Upon reception of signals, the weighted signals of each pattern are summed together, multiplied by cosinusoidal and sinusoidal reference signals and then summed together to provide a radiation pattern which converges from the array to a focal point in front of the array while eliminating a diverging pattern from a virtual focus behind the array.

Abstract: In a rotating probe ultrasonic system the effective PRF may not be sufficiently high for certain purposes, such as examination of the foetal heart. The invention combines fixed transducers looking at a limited region with a rotating probe scanning over a larger region to give a higher effective PRF in the limited region. The two displays are preferably separate although the display of the larger region may conveniently indicate the location of the limited region.

Abstract: An ultrasound diagnostic apparatus includes a linear array of piezoelectric transducers or plates with a width-to-thickness ratio of less than 0.8 and a control circuit which includes a transmitter and a receiver. The transmitter comprises a plurality of transmitting channels each including a local oscillator for generating an ultrasonic pulse in response to a clock signal. The plurality of such ultrasonic pulses are applied through a switching network to a selected group of successively arranged piezoelectric transducers to transmit a beam of ultrasonic energy into a human body. Each of the ultrasonic pulses is phase shifted and amplitude modulated with respect to the ultrasonic pulses of the other transmitting channels to provide phase and amplitude taper which results in a narrow width beam through the depth of the body.

Abstract: A variable delay system in which multistage delay lines are "shared" between different elements (e.g. different transducer elements or segments). A plurality of delay lines are provided, the delay lines having respectively different numbers of stages. The signals from the first and last segments of a segmented transducer are applied to opposing ends of the delay line having the largest number of stages. The signals from the second and next-to-last segments of the transducer are applied to opposing ends of the delay line having the next-to-largest number of stages, and so on. A plurality of coupling circuits are respectively associated with the plurality of delay lines and are operative to sample, as a function of time, the signals at different delay stages of their respective delay lines. The outputs of the coupling circuits are combined to form an image-representative signal.

Abstract: A ring of transmitter and receiver transducer arrays circumbscribes an object to be scanned. Semicircular wave fronts of ultrasound energy are propagated from different points around the ring of transducers by triggering the transmitter arrays in sequence. The reflected and transmitted ultrasound energy picked up by the receiver arrays is then electronically analyzed and a synthetically focused image corresponding to the scanned object is reconstructed on a display screen. Surprisingly high quality resolution for the reconstructed images is achieved by carefully controlling the type of waveform from which the displayed image is reconstructed. In one embodiment of the invention, the signals received by the receiver arrays are processed by a waveshaping circuit to achieve the desired waveform. In a second embodiment of the invention, the desired waveform is generated by a waveform generator circuit and transmitted by the transmitter arrays.

Abstract: A device for scanning and display by means of ultrasonic waves, comprising an electro-acoustic converter including a rectangular matrix of transducers. A number of switching members are adapted to select a rectangular scanning zone in the matrix, to group the transducers in the scanning zone in annular concentric configurations, and to displace the scanning zone in the longitudinal direction of the matrix.

Abstract: Disclosed is a method for transmission and reception of ultrasonic beams using an array of ultrasonic transducer elements in which a plurality of transducer element sets each including the selected number of transducer elements for the transmission and/or reception of ultrasonic beams are sequentially selected. First and second sets having different focal axes defined relative to the plane of the transducer array are selected for the transmission and reception modes of operation respectively during the production of a single scan line. The position of at least one of the transducer elements in the first set is different from those of the transducer elements in the second set.

Abstract: An underwater apparatus is described for acoustically inspecting a submerged object at considerable depths such as the lower structural portion of an off-shore drilling rig to determine if the structure has internal defect which cannot be optically detected. The apparatus is intended to operate in depths of up to 500 meters. The apparatus includes an underwater craft for transporting both humans and equipment to the submerged object. The apparatus includes a hand held acoustical and optical probe that is movable by a diver over the surface of the submerged object. The probe includes an array of acoustical transducers that are sequentially activated to acoustically scan the interior of the object. The acoustical transducers are mounted in a flexible support material to accommodate the array to the contour of the surface. The probe additionally includes a real-time display of the acoustical information to assist the diver in effectively inspecting the object.

Abstract: The invention relates to ultrasonic systems for the visual display of a thin section of a body. The subject of the invention is a system wherein the multi-element scanning probe which picks up or transmits the ultrasonic energy cooperates with an array of elastic-surface-wave transducers and with a group of frequency converter circuits in order to constitute an ultrasonic lens. The invention is more particularly applicable to the non-destructive examination of bodies permeable to ultrasonic energy such as is practiced for example in medicine and when industrial goods are being checked.

Abstract: An apparatus for ultrasonically measuring concentrations of stress in objects of interest. The apparatus includes an ultrasonic transducer array for propagating acoustic waves in an object of interest along a plurality of determinable directions and from a plurality of determinable positions. A time interval counter measures the time of flight of the acoustic waves along the determinable directions and from the determinable positions. The time of flight measurements are reconstructed into a map of the variations in acoustic velocity within the object. The changes in acoustic velocity are then mathematically converted into a map of stress concentration areas in the object of interest.

Abstract: An ultra-sonic echography apparatus comprises a probe with multiple elements switched at the rate of transmission pulses and moved along a contour of the test body. Its position is registered by a pantograph cooperating with three sine-cosine potentiometers, the sine potentials of which control the horizontal deflection plates of a cathode-ray tube, while the cosine potentials control the vertical deflection plates and a fourth potentiometer adds potentials displaced by 90.degree. with respect to those delivered by the said three potentiometers, so as to control the beam position of the cathode ray tube for obtaining, on the screen thereof, a beam trace which is homothetic with respect to the ultrasonic beam in the test body.

Abstract: An electronically scanned phased array diagnostic system for describing internal structure of a subject by the use of ultrasonic energy. The system includes a transducer unit with an array of ultrasonic energy conversion segments and control circuitry for actuating the segments to direct ultrasonic energy into the subject. Imaging circuitry is included for interpreting electrical return signals produced by the segments in response to ultrasonic echoes. The imaging circuitry includes transmission delay circuits for imposing time delays on the return signals for steering and focusing system echo reception. Each transmission delay circuit includes first and second delay elements for impressing first and second delay time components on the return signals. Each pair of the first delay elements are coupled in parallel with separate transducer elements, and serially combined with a downstream second delay element.The first delay elements provide a portion of the reception steering capability.

Abstract: In an ultrasonic investigating apparatus a transducer can receive reflections from points in the body for which the position in one direction is relatively well known as a result of accurate range gating but for which the position in another direction is relatively less known in view of the relatively wide ultrasound beams used. Thus the reflections are only known as originating from lines in the body. These line integrals of reflection of ultrasonic energy are processed by methods appropriate to line integrals in general, as known for line integrals of X-ray absorption for example, to more accurately position the reflecting points in the body. A propagation velocity distribution can also be determined for the body to further improve the accuracy.

Abstract: A probe unit including a plurality of ultrasonic fault detection probes is moved along an object to be examined by a probe drive unit. The fault detection signals produced by the probes are transfer switched among a plurality of channels of a channel selector and the output of the channel selector is sampled by a high speed sampling device. A computer is connected to the probe drive unit, channel selector and the sampling device to apply operating signals thereto and to receive the outputs thereof.

Abstract: An ultrasonic diagnostic apparatus is provided comprising a clock pulse generator, and electro-acoustic transducer which responds to the clock pulse from the clock pulse generator to produce an ultrasonic wave, a receiving circuit for receiving the electrical signal from the electro-acoustic transducer, a variable gain amplifier for amplifying the output signal from the receiving circuit, a display device for displaying information corresponding to the signal from the amplifier, and a gain control circuit for controlling the gain of the variable gain amplifier.

Abstract: The invention relates to a probe for a device forming images from ultrasounds, in particular for the internal examination of the human body. The probe comprises transducers distributed in a curved array providing the possibility of a sectorial angular scanning and of generating ultrasonic beams converging towards a localized area where is arranged either a screen opaque to ultrasounds and formed with one or two openings in the vicinity of the center of converging area, with one or two lenses for ultrasounds in said opening or openings, either one or two electronic lenses formed with means for converting in parallel ultrasounds into electric signals, apparatus for differentially delaying the electric signals and apparatus for converting in parallel the electric signals, after a delay, into ultrasounds.

Abstract: This specification discloses an apparatus for scanning acoustic waves in accordance with the movement of a presumed axis moving on a certain surface (plane or curved). This apparatus has a multiplicity of acoustic transducer elements arrayed in the direction of movement of the presumed axis (scanning direction). The multiple acoustic transducer elements are grouped into a plurality of sets. At least two of the plurality of sets are associated with, namely, transmit or receive, a predetermined number of wave fronts overlapping one another within a predetermined region of the presumed axis and having their centers of curvature outside the axis as it moves. Thus, there is obtained an effect equivalent to that achieved by throwing thin acoustic beam along the presumed axis or by detecting the acoustic wave at each point on the axis preferentially from the other portions outside of such axis.

Abstract: An ultrasonic diagnosing apparatus effects high speed ultrasonic scanning of a subject to be examined and produces and records a plurality of closely spaced, planar B-mode tomographic images. The diagnosing apparatus includes an ultrasonic probe having a linear array of ultrasonic converters, a mechanical apparatus to move the probe in a direction broadside to the linear array, an ultrasonic transmitting and receiving device for activating the electroacoustic converters and processing signals from the electroacoustic converters to form a plurality of closely spaced, planar B-mode tomographic images, a display device and a continuous recording device.

Abstract: An object surrounded by media of differing acoustical impedances (e.g., an anatomical organ surrounded by other kinds of tissue within the human body) is acoustically imaged by an array of ultrasonic transducers affixed to the outer surface of an ultrasonic lens. In a preferred embodiment, the lens is homocentric, with the common center of curvature of the inner and outer surfaces of the lens being located at a relatively small acoustic aperture in the body so that object points distributed over a relatively large solid angle from the aperture can be imaged with minimum lens aberations. Where the object to be imaged is a human heart, the acoustic aperture is most conveniently located at an intercostal space between adjacent ribs.

Abstract: A linear transducer array with low overall side lobe sensitivity for use in steered beam imagers has a different interelement spacing for transmit than for receive, and preferably has a shorter transmit array with elements spaced at one-half wavelength as the center portion of a longer receive array whose unit elements are spaced at a full wavelength. Two or more elements in the center portion can be coupled together to a receiving channel to maintain constant spacing for the receive aperture in a 100% active transducer.

Abstract: A curved transducer array or a flat array with an acoustic converging lens functions as a fixed focus physical lens and is focused near maximum range. At longer ranges the full aperture is utilized for good resolution, and at shorter ranges up to a specified fraction of maximum range improved resolution is achieved by a dynamic aperture control which increases the array aperture by steps by switching in more transducer elements. This simplified sector scanner does not require dynamic electronic focusing.

Abstract: A B-scan ultrasonic imager such as a single-sector scanner has a dynamic aperture and focus control to attain improved lateral resolution especially at ranges less than the maximum array aperture. As the range from which echoes are being received propagates out, the array aperture during each echo reception period is increased by steps by switching in more elements of the total transducer array. At least one adjustment of receiving channel time delays is made to dynamically focus the echoes at different focal points.

Abstract: In the illustrated embodiment, an electronic receiving gate is inserted between the image display device and the ultrasonic echo receiver so as to allow only echo impulses from a selected depth of field to pass through to the image display device. The depth selection is effected without any change in the line and image scanning rates by shifting the receiving gate between its transmitting and blocking states in the rhythm of the line sweep pulses and by adjusting the moment of emission of the ultrasonic pulses within the blocking phase of the receiving gate.

Abstract: A linear transducer array for transmitting and receiving acoustic waves in both pulse-echo and holographic modes of operation. For pulse-echo acoustic imaging the array includes a linear subarray of transmitting transducer elements disposed in a plane along a longitudinal axis. Each transmitting element has an elongate shape and a principal axis that is perpendicular to the longitudinal axis of the array. For holographic imaging the apparatus further includes a removable mechanical shutter for blocking a predetermined portion of the principal axis of each of the transmitting elements so that a dispersive acoustic beam can be generated. The array also includes a linear subarray of receiving transducer elements coplanar with the transmitting subarray and disposed parallel to the longitudinal axis. The subarray of receiving elements is used to detect the reflected acoustic waves for both holographic and pulse-echo imaging.

Abstract: A transducing unit comprising a central section, detecting echoes returned through only a small portion of a relatively large aperture lens, surrounded by an annular section, detecting echoes returned through the remainder of the aperture, provides detected signals from the respective central and annular sections which are selectively utilized during respective specified time intervals in accordance with the operation of time-controlled switches to thereby change the effective depth of focus of the lens as a function of time.

Abstract: In the illustrated embodiment, ultrasonic transmitter/receiver elements are arranged along a curved formation within a housing containing a coupling medium which is a good conductor of ultrasonic energy (for example a water medium) and are successively excited to direct ultrasonic beam energy via the coupling medium to an ultrasonic window of the housing. The transducer elements are mounted at different angular orientations such that their beam paths converge external to the ultrasonic window. The curvature of a carrier for the transducer elements may be controlled to adjust the distance of the point of convergence beyond the window without changing the length of the acoustic path in the coupling medium, or the transducer elements and/or ultrasonic window may be bodily shifted to simultaneously change the length of the acoustic path and the distance of the convergence point beyond the window.

Abstract: The illustrated apparatus comprises an ultrasonic array and an actuating system for actuating the transducer elements of the array in groups with an alternating number of transducer elements. Actuation proceeds, in an interlaced transmission/receiving cadence, in groups with an even-numbered and in groups with an odd-numbered count of transducer elements such that each connected even-numbered and odd-numbered group, in relation to the previously connected group, is, in a first clock interval, first receiver for the echo signals of the transmission beam of the preceding group, and, in a following clock interval, is switched over to transmission. The apparatus is used particularly in electromedical ultrasonic sectional image diagnosis.

Abstract: An electrical-to-acoustic wave transducer contains an array of piezoelectric elements connected to wave-delay circuits to generate a directed acoustic beam and to receive a similarly directed, reflected beam. The distance of a reflecting object is sensed by the time delay of the reflected wave. The apparatus is adapted to sense reflections from both the Fresnel region and the far-field of the array. During the time when reflections from nearby objects in the Fresnel region are received, the effective aperture of the array is reduced by disconnecting elements near its extremities or reducing their gain, producing a narrower beam for improved angular resolution.

Abstract: A steered beam B-scan ultrasonic imaging system has a linear transducer array divisible into multiple sub-arrays of transducer elements each operable to perform a sector scan, with the origin points displaced longitudinally along the array between sector scans. The system performs overlapping sector scans and is capable of imaging randomly oriented specularly reflecting targets. Time delays in the transmitting and receiving channels to steer the transmitted beam and to focus the received echoes are provided by digital techniques, by reversible digital shift registers, or by charge coupled device delay lines. The multiple sector image is displayed in real time in an intensity versus displacement format on a cathode ray tube.

Abstract: The combination of a "C" mode scan electronics in a portable, battery powered biomedical ultrasonoscope having "A" and "M" mode scan electronics, the latter including a clock generator for generating clock pulses, a cathode ray tube having X, Y and Z axis inputs, a sweep generator connected between the clock generator and the X axis input of the cathode ray tube for generating a cathode ray sweep signal synchronized by the clock pulses, and a receiver adapted to be connected to the Z axis input of the cathode ray tube.

Abstract: A real time ultrasound imaging system provided with a fixed focus and including coherent demodulation of echo signals followed by time delay and coherent summation of the demodulated signals is described. As the range from which echoes are being received increases, coherent demodulation is maintained. Demodulation and time delay accuracies are relatively easy to maintain over a large field of view and a long range. The system has high resolution and high sensitivity.

Abstract: A B-scan ultrasound probe imaging system including an array of annular transducers is described in which dynamic focussing is provided by coherent demodulation of the echo signals generated in the transducers. As the range from which echoes are being received increases, coherent demodulation is maintained. The system provides improved lateral resolution over a greatly extended useful range.

Abstract: A real time ultrasound imaging system which includes coherent demodulation of echo signals followed by time delay and coherent summation of the demodulated signals is described. As the range from which echoes are being received increases, coherent demodulation is maintained. Demodulation and time delay accuracies are relatively easy to maintain over a large field of view and a long range. The system has high resolution and high sensitivity.

Abstract: A real time ultrasound imaging system which includes coherent demodulation of echo signals followed by time delay and coherent summation of the demodulated signals is described. As the range from which echoes are being received increases, coherent demodulation is maintained. Demodulation and time delay accuracies are relatively easy to maintain over a large field of view and a long range. The system has high resolution and high sensitivity.

Abstract: Ultrasonic phased array method and apparatus for the static or dynamic investigation of structures, such as organs of the body, or intra-uterine detail, wherein ultrasonic echo pulses, reflected back from a testpiece to one or a group of adjacent transducers of a linear transducer array, are converted to corresponding electric signals which are then processed to maximize the response to the echo pulses reflected from points on a predetermined axis and to minimize the response to all other echo pulses. The method is repeated using another group of transducers in the array and another predetermined axis to produce fields of video information which are focussed and then interlaced to provide an image of the testpiece at a particular instance, the method steps being repeated in rapid succession to provide a video image representative of the testpiece in real time.

Abstract: An ultrasonic transducer probe having a sealed rotor housing, a plurality of transducers mounted on a rotor disposed in said housing. A rotor shaft mounts the rotor and extends through the housing. A drive assembly including commutating and position indicating means receives said housing and rotor shaft and serves to drive the rotor, commutate electrical energy to and from said transducers and indicate the angular position of said rotor. A handle including means for driving said drive assembly is attached to said drive assembly to position the rotor housing and drive assembly against the body the rotate said rotor to cause the transducers to scan a sector of the body.

Abstract: An imaging system, particularly useful for acoustic medical diagnosis of a human subject, utilizes an array of radiating elements or sonic transducers located side-by-side and positioned along the subject. Signals received by the transducer are applied to a pair of pattern generation circuits which weight the individual signals by factors of +1, -1 or 0. Graphs of the weighting factors as a function of transducer location have the likeness of cosinusoidal and sinusoidal Fresnel patterns, these patterns being produced by the two circuits. The weighted signals of each pattern are summed together, multiplied by cosinusoidal and sinusoidal reference signals and then summed together to provide a radiation pattern which converges from the array to a focal point in front of the array while eliminating a diverging pattern from a virtual focus behind the array.

Abstract: An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

Abstract: An ultrasonic scanner for producing a sector scan in an object to be examined in which one or more ultrasonic transducers traverse an arcuate path with respect to a reflector which is positioned to receive the ultrasonic waves scanning the surface of the reflector from each of the transducers and converge such waves at a point of a preselected distance in front of the reflector. In general, the ultrasonic waves are converged at a point outside the scanner and inside the object to produce a sector scan in the object having its center at the convergence point. In one embodiment of the scanner the reflector only partially reflects the ultrasonic waves and an additional stationary transducer is provided which is positioned to produce ultrasonic waves which radiate through the reflector and coincide with one of the lines of the sector scan, thus permitting simultaneous M-mode or pulse Doppler echo information to be obtained in perfect registration with the sector scan lines.

Abstract: An echoscope for examination of objects with the aid of an ultrasound beam, comprising at least one electro-acoustic element for transmitting and receiving ultrasonic pulses during a transmission-reception period divided into n consecutive time intervals. The ultrasonic pulses are sent to the objects to be examined and are reflected therefrom. The echo signals supplied by the receiving element are amplified by an amplifier with time-dependent gain control. The gain control is brought about by a control voltage generator which supplies a control voltage to said amplifier for determining its signal gain as a function of time. Adjusting means for the control voltage generator are provided to make it possible to change the magnitude of the control voltage in the time intervals as a function of time. The apparatus also comprises a device for visually displaying the echo signals received during each transmission-reception period.

Abstract: An array of transducers is provided for transmitting pulses of ultrasonic pressure waves into a body and translating reflections received into corresponding pulses of electrical waves. Phase changing means, which may preferably include heterodyning means, are connected between each transducer and selected taps on one delay line. The taps are just close enough together to provide reasonable overlap of the pulses of electrical waves at the summing point at one end of the delay line. Focussing is attained by adjusting the phases of the waves applied to each tap so that the cycles of carrier wave within the overlapped portion of the pulses at the summing point have reasonable phase coherence.

Abstract: An ultrasonic transducing unit comprising a central section, which cooperates with only a small portion of the relatively large aperture of an acoustic lens, and an annular section, which cooperates with the remainder of the aperture, can be selectively operated by switch means to utilize the relatively large depth of focus detected signal of the central section alone or to utilize the relatively small depth of focus detected signal of both the central and annular sections together.

Abstract: Non-destructive testing with ultrasonic energy is performed by scanning a focused ultrasound beam until a region of interest is detected and rescanning this region with the beam focused at a plurality of depths. Apparatus for ultrasonic body scanning for medical purposes may include an actively driven transducer crystal which may be dynamically focused. A beam of energy produced by the transducer will be coupled to the patient by a liquid path and a movable mirror may be interposed along the liquid path to cause scanning of the beam.

Abstract: In an ultrasonic investigating apparatus a transducer can receive reflections from points in the body for which the position in one direction is relatively well known as a result of accurate range gating but for which the position in another direction is relatively less known in view of the relatively wide ultrasound beams used. Thus the reflections are only known as originating from lines in the body. These line integrals of reflection of ultrasonic energy are processed by methods appropriate to line integrals in general, as known for line integrals of X-ray absorption for example, to more accurately position the reflecting points in the body. A propagation velocity distribution can also be determined for the body to further improve the accuracy.